<template>
  <div>
    <input v-model="demo.name" type="text" name="" id="">
    {{value}}
  </div>
</template>
<script>
  export default {
    name: 'index',
    data() {
      return {
        demo: {
          name:''
        },
        value: ''
      };
    },
    computed:{
      newname(){
        return this.demo.name
      }
    },
    watch: {
      newname(val) {
        this.value = val;
      }
    }
  };
</script>